cold start bug for embedding tier #25

Pre-flight

• I searched existing issues and this is not a duplicate.

Summary

if the embeddings get called first before there's been any lexical calls, embedding_resolver_active runs before the graph has been set up, which needs _get_kg t have run

Reproduction

cold start, make single search

Actual behaviour

on the first query a fresh server receives, the embedding tier is never planned - embedding_tier_detail stays empty

Expected behaviour

have embedding_resolver_active, or the start of grounding, call _get_kg() before the tiers are built, or set up the graph at server start

Error output

System info